Glaucoma is a medical condition where increased pressure within an eyeball causes a gradual loss of sight. Although glaucoma can not be cured, if detected early enough it can be controlled by medications, surgery, or both. In any case, the important thing is to have early detection. In the early stages of the disease, however, there are few detectable symptoms that are glaucoma specific. Nevertheless, there are certain risk factors, such as age, race, and family history, in addition to hypertension, which can indicate that an early detection (prediction) of glaucoma may be prudent. Stated differently, it may be desirable to identify candidates early on for the pharmacological treatment of glaucoma. And, consequently, to thereby determine a properly required pharmacological regimen, including the type and strength of medications to be used.
It is known that an increased intraocular pressure (IOP) inside the eyeball causes glaucoma. An increased IOP also causes noticeable anatomical changes in the eye. In particular, as a consequence of the increased IOP, changes in biomechanical stress conditions in the Lamina Cribrosa (LC) of the Optical Nerve Head (ONH) are observable. Importantly, these observations can be evaluated to determine whether any damage to the LC is due to an increase in IOP. If so, glaucoma may be indicated. On the other hand, a healthy eye, without glaucoma, will resist the cell damage that would otherwise be caused by an increase in IOP.
Anatomically, the LC is generally a cylindrical-shaped, mesh-like structure that includes pores which pass through the structure. It is located at the back of an eye, and is positioned in a hole through the sclera at the ONH where fibers of the optic nerve exit the eye. In addition to supporting these nerve fibers, it is believed that an important function of the LC is to help maintain an appropriate pressure gradient between the inside of the eye (i.e. IOP) and the surrounding tissue. For this purpose, the LC is more sensitive to pressure differences than is the thicker, denser sclera surrounding the ONH. Consequently, it tends toward a measurable change in its configuration with increased IOP. Importantly, it is believed that configuration changes in the LC contribute to glaucoma.
Mathematical models of anatomical structures, such as components of the eye, can be very helpful diagnostic tools. In particular, whenever an anatomical structure is somehow forced to change, a Finite Element Model (FEM) is known to be helpful for evaluating the consequences of the change. For example, U.S. patent application Ser. No. 12/205,420 for an invention entitled “Finite Element Model of a Keratoconic Cornea” which is assigned to the same assignee as the present invention, discloses a mathematical methodology for predicting the condition of an eye in response to a proposed surgical procedure.
In light of the above, it is an object of the present invention to provide a system and method for predicting the onset of glaucoma before symptoms of the disease become apparent. Another object of the present invention is to identify candidates for the pharmacological treatment of glaucoma, and to provide information for subsequently establishing the treatment regimen. Yet another object of the present invention is to provide a system and method for mathematically modeling the Lamina Cribrosa (LC) to create a pressure response profile for comparison with empirical data to predict the onset of glaucoma. Still another object of the present invention is to provide a system and method for predicting the onset of glaucoma that is easy to implement, is simple to use and is comparatively cost effective.